Continuous passive motion therapy has long been known to provide significant benefit during the post-surgical or injury-treatment phase of such things as orthopedic replacements, adhesive capsulitis, manipulation under anesthesia, anterior stabilization, fixed proximal humeral fractures, synovectomies, rotor cuff repairs, subacromial decompressions, surgical reconstructions, shoulder arthroplasty, acromioplasty, soft tissue surgery in the axilla or in the shoulder girdle area, stabilized fractures, burns, and at other times such as in cases of arthritis or muscular dystrophy to mention but a few.
While physical therapists are often used to provide such therapy, their treatments are generally expensive and such skilled individuals are not always available when they are needed. As a consequence, there have been many attempts in the past to develop apparatus capable of providing continuous passive motion therapy.
Among these devices may be mentioned articulated structures designed to bear the limbs to be reeducated. Such structures, often associated with complicated systems of pulleys, cables and counter weights, can provide stability while admitting of relative displacement through pivoting motions. Although these systems provide passive mobilization, they have an unfortunate tendency to be cumbersome and difficult to adjust properly so as to fit a particular patient's need.
One passive motion device, shown in U.S. Pat. No. 5,179,939, teaches a shoulder exerciser which moves a patient's arm reciprocally back and forth through an arc of up to 180 degrees, thereby providing both flexion and abduction of the shoulder. The arm holder of the device is slidably and pivotally mounted so that the patient's arm can move toward and away from the patient's body, pivoting in order to allow the shoulder joint to follow a neutral anatomical range of motion.
Yet another such device is taught in U.S. Pat. No. 4,651,719 which discloses a portable apparatus that fits against the user's torso. Adduction and abduction of the arm are made possible by a lineal actuator extending between the base of the device and an upper arm support. Additional linkage is provided in order to permit rotation of a forearm support as the upper arm support is pivoted.
Notwithstanding the preceding and numerous other attempts to provide continuous passive motion to patients in need of the same, it has been difficult to design a device that imparts a desired passive treatment to the user's shoulder. In part, this has been the result of the fact that the shoulder is formed by the lateral juncture of the body's clavicle, scapula, and humerus. Such a structure produces a ball-and-socket-type of articulation between the proximal humerus and the glenoid cavity of the scapula. The socket of this structure is shallow, however, and the joint capsule is loose-fitting as a consequence. While the joint permits a wide range of motion, it has rather poor stability and inferior strength.
Furthermore, where two separate and distinct passive motions of the arm and shoulder are attempted simultaneously, for example, where lateral rotation of the arm is initiated at the same time that the arm's elevation is undertaken, it is unfortunately possible to simultaneously encounter angular positions of rotation and elevation that are physiologically incompatible with each other. When such positions are encountered, unless the situation is immediately recognized and movement of the device into the conflicting configuration avoided, severe trauma to the patient being exercised can easily occur, particularly in the shoulder area which is naturally weak as described.
One of the disadvantages of passive exercise machines of the type commonly employed prior to the device disclosed herein is that they often provide adjustment ranges of their several movements which allow combinations of motions that can be antagonistic relative to each other, either anatomically, or because of the nature of the condition responsible for the need to undergo therapeutic treatment. This fact coupled with the fact that passive motion exercise machines can be often used by untrained persons, and without proper supervision, presents a real risk that the devices will be used improperly and that injuries will result as a consequence thereof.
In view of the foregoing, therefore, it is a first aspect of this invention to provide an improved continuous passive motion exercise device.
A second aspect of this invention is to provide a continuous passive motion exercise device that provides elevation of the arm, as well as the rotation thereof.
An additional aspect of this invention is to provide a continuous passive motion exercise device in which the elevation drive means and the rotation drive means are coordinately controlled by an electronic microcontroller.
A further aspect of this device is to provide a continuous passive motion exercise machine in which the elevation drive means and the rotation drive means are subject to control by a programmable electronic microcontroller that prevents physiologically incompatible positioning of the limbs being manipulated.
Another aspect of this invention is to provide a continuous passive motion exercise device that avoids injuries caused by the device to individuals using the same.
Yet an additional aspect of this invention is to provide a continuous passive motion exercise device capable of exercising an individual's arm in one of two separate motions; in two different motions conducted simultaneously; or in two different motions performed sequentially.
Still a further aspect of this invention is to provide a continuous passive motion exercise device equipped with an orthosis designed to minimize the effects of misalignment between the pivot point of the device's elevation drive mechanism, and the pivot point of the patient's shoulder.